Replace pending_tasks.merge with AtomicI32

This change moves the `merge` field out of
`Rav1dFrameContext_task_thread_pending_tasks` into the parent struct,
`Rav1dFrameContext_task_thread`, in preparation to move the
`pending_tasks` field into a Mutex.

src/internal.rs

@@ -412,7 +412,6 @@ pub struct Rav1dFrameContext_lf {
 
 #[repr(C)]
 pub struct Rav1dFrameContext_task_thread_pending_tasks {
-    pub merge: atomic_int,
     pub lock: pthread_mutex_t,
     pub head: *mut Rav1dTask,
     pub tail: *mut Rav1dTask,
@@ -442,6 +441,7 @@ pub(crate) struct Rav1dFrameContext_task_thread {
     // [head;cur-1] when picking one for execution.
     pub task_cur_prev: *mut Rav1dTask,
     // async task insertion
+    pub pending_tasks_merge: AtomicI32,
     pub pending_tasks: Rav1dFrameContext_task_thread_pending_tasks,
 }
 

src/lib.rs

@@ -103,6 +103,7 @@ use std::mem;
 use std::mem::MaybeUninit;
 use std::process::abort;
 use std::ptr::NonNull;
+use std::sync::atomic::AtomicI32;
 use std::sync::atomic::Ordering;
 use std::sync::Arc;
 use std::sync::Once;
@@ -896,8 +897,7 @@ pub(crate) unsafe fn rav1d_flush(c: *mut Rav1dContext) {
             *fresh5 = 0 as *mut Rav1dTask;
             *&mut (*((*c).fc).offset(i_1 as isize))
                 .task_thread
-                .pending_tasks
-                .merge = 0 as c_int;
+                .pending_tasks_merge = AtomicI32::new(0);
             i_1 = i_1.wrapping_add(1);
         }
         *&mut (*c).task_thread.first = 0 as c_int as c_uint;

src/thread_task.rs

@@ -318,22 +318,23 @@ unsafe fn add_pending(f: *mut Rav1dFrameContext, t: *mut Rav1dTask) {
         (*(*f).task_thread.pending_tasks.tail).next = t;
     }
     (*f).task_thread.pending_tasks.tail = t;
-    ::core::intrinsics::atomic_store_seqcst(&mut (*f).task_thread.pending_tasks.merge, 1 as c_int);
+    (*f).task_thread
+        .pending_tasks_merge
+        .store(1, Ordering::SeqCst);
     pthread_mutex_unlock(&mut (*f).task_thread.pending_tasks.lock);
 }
 
 #[inline]
 unsafe fn merge_pending_frame(f: *mut Rav1dFrameContext) -> c_int {
-    let merge = ::core::intrinsics::atomic_load_seqcst(&mut (*f).task_thread.pending_tasks.merge);
+    let merge = (*f).task_thread.pending_tasks_merge.load(Ordering::SeqCst);
     if merge != 0 {
         pthread_mutex_lock(&mut (*f).task_thread.pending_tasks.lock);
         let mut t: *mut Rav1dTask = (*f).task_thread.pending_tasks.head;
         (*f).task_thread.pending_tasks.head = 0 as *mut Rav1dTask;
         (*f).task_thread.pending_tasks.tail = 0 as *mut Rav1dTask;
-        ::core::intrinsics::atomic_store_seqcst(
-            &mut (*f).task_thread.pending_tasks.merge,
-            0 as c_int,
-        );
+        (*f).task_thread
+            .pending_tasks_merge
+            .store(0, Ordering::SeqCst);
         pthread_mutex_unlock(&mut (*f).task_thread.pending_tasks.lock);
         while !t.is_null() {
             let tmp: *mut Rav1dTask = (*t).next;
@@ -490,7 +491,9 @@ pub(crate) unsafe fn rav1d_task_create_tile_sbrow(
         (*(*f).task_thread.pending_tasks.tail).next = &mut *tasks.offset(0) as *mut Rav1dTask;
     }
     (*f).task_thread.pending_tasks.tail = prev_t;
-    ::core::intrinsics::atomic_store_seqcst(&mut (*f).task_thread.pending_tasks.merge, 1 as c_int);
+    (*f).task_thread
+        .pending_tasks_merge
+        .store(1, Ordering::SeqCst);
     (*f).task_thread.init_done.store(1, Ordering::SeqCst);
     pthread_mutex_unlock(&mut (*f).task_thread.pending_tasks.lock);
     Ok(())